A harsh 5-4 downshift can be felt during deceleration while braking or coasting

Bulletin number

LI27.60-P-078599

Component

Power train

Summary

Complaint A harsh 5-4 downshift can be felt during deceleration while braking or coasting. It may be mistaken for a hard brake engagement Cause In certain driving scenarios, the transmission torque adaptation for the 5-4 downshift is recorded at a higher value. This skews the learning which leads to harsh engagement of the B06 clutches, creating the harsh 5-4 downshift. Remedy "Phase 1" software was released 11/14/2024 to slow the adaptation process and reduce the frequency of the complaint. However, it was possible that the client’s driving style could cause suboptimal adaptations, and this would result in the concern returning sooner than anticipated for some vehicles. "Phase 2" software has been released as of 09/04/2025 and will correct the root cause of the poor adaptation learning. See software list below. A0019021721 A0019021821 A0019021921 A0019022021 A0019022121 Please follow IPR recommended procedures. IPR has been trained to recognize this pattern and will advise the necessary steps below. ALL STEPS MUST BE PERFORMED! The concern will still be present or may return if not completely correctly. Ensure all steps are documented in paperless, the previous warranty print out with the check marks is no longer required. 1. Perform resetting of learned values "deceleration mode" (VGS > Special Procedures > Special procedure > Resetting learned values Deceleration mode) 2. Perform 5 standstill adaptions in a row followed by 5 torque converter adaptations 3. Perform software update for the VGS Control Unit 4. Clear all faults 5. Perform final QC test drive & confirm normal operation of all shifts If issues arise during the process or the concern has returned with phase 2 software, please submit a TIPS case to the Powertrain inbox with the following information: - Initial Quick Test w/ freeze frame data - VGS Control Unit Log - Initial EEPROM data (before any procedures) - Current EEPROM data (after LI/IPR procedures) - Relevant screenshots (standstill adaptations, software update, etc)

Owners of these vehicles have filed 7 complaints in the transmission category.